I just purchased a GK 700rb-II and GK neo 410 setup, both used, and Im not sure if it's sounding the way it should. There is little to no sound coming from the horn in any mode, in bi-amp if I turn the woofer all the way down I can hear the tweeter but it's volume is low with rattles and hissing. Also the attenuation knob for the horn is missing off the back of the cab so I have no idea where it is set to. If someone could help me out that would be great.